Polymer monolith containing an embedded covalent organic framework for the effective enrichment of benzophenones

A covalent organic framework (COF) is an intriguing porous material with unique properties and can be promisingly used as a functional material for microextraction. In the current study, a COF was introduced into a poly(glycidyl methacrylate-ethylene dimethacrylate) monolith inside a capillary via photo-induced thiol-epoxy click polymerization to prepare a novel polymer monolith microextraction material. The COF functionalized monolith was characterized using scanning electron microscopy, Fourier-transformed infrared spectroscopy, X-ray photoelectron spectroscopy, and thermal gravimetric analysis. Under optimized conditions, acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations were obtained for benzophenones by coupling with an HPLC instrument. The developed method was employed for the preconcentration and determination of benzophenones in human urine and serum samples and was assessed through recovery studies.